<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    .book {
      perspective: 1000px;
      position: relative;
      width: 200px;
      height: 300px;
    }
    .cover {
      position: absolute;
      width: 100%;
      height: 100%;
      background-color: #f2f2f2;
      transition: transform 0.6s;
    }
    .page {
      position: absolute;
      width: 50%;
      height: 100%;
      background-color: #e0e0e0;
      transform-origin: left;
      transition: transform 0.6s;
    }
    .book:hover .cover {
      transform: rotateY(-180deg);
    }
    .book:hover .page {
      transform: rotateY(0deg);
    }
  </style>
</head>
<body>
  <div class="book">
    <div class="cover"></div>
    <div class="page"></div>
  </div>
</body>
</html>